MECHANISM OF BREFELDIN A ACTION

布雷菲德菌素A（Brefeldin A，BFA）是一种具有广泛生物活性的真菌代谢产物， 活性，包括抗真菌和抗肿瘤活性。 过去 几年来，人们对它对细胞的影响产生了极大的兴趣， 因为已经发现它具有独特的干扰 细胞中的小泡运输。 在它的影响中，它分散了 高尔基复合体，至少将其部分成分返回到 内质网（ER）。 BFA还可以阻止新合成的蛋白质 注定要到达细胞表面而离开ER。 此属性是 负责其完全阻断病毒呈递的能力 细胞毒性T淋巴细胞的抗原。 为了更好地了解该机制 的BFA的作用，我们共轭它到两个荧光染料，并研究其 细胞内定位 两种缀合物均保持其生物学特性。 活性，并且都特异性地定位于ER和高尔基复合体， 活的或固定的细胞。 本地化是特定的，因为 非共轭染料，或与类似结构的分子共轭的染料 BFA不表现出相同的定位模式。 选择性 将结合的BFA分配到细胞内膜中可能是 由于其与脂质的相互作用， 提取脂质。 这些缀合物是结合所述抗体的第一染料。 ER与高尔基体复合体无结合，其它突出膜结合 隔室，并应证明这些细胞器的探针有用 在活细胞中。BFA与内质网和高尔基复合体的相互作用 膜可能是其对囊泡运输的影响所必需的。

Brefeldin A (BFA) is a fungal metabolite with a broad range of biological activities, including antifungal and antitumor activities. In the past few years there has been tremendous interest in its effects on cells, since it has been found to have a unique ability to interfere with vesicular trafficking in cells. Among its effects, it disperses disperse Golgi complex, returning at least some of its components to the endoplasmic reticulum (ER). BFA also prevents newly synthesized proteins destined for the cell surface from leaving the ER. This property is responsible for its ability to completely block the presentation of viral antigens to cytotoxic T lymphocytes. To better understand the mechanism of BFA action, we conjugated it to two fluorescent dyes and studied its intracellular localization. Both conjugates maintained their biological activity, and both specifically localized to the ER and Golgi complex in live or aldehyde-fixed cells. Localization is specific since unconjugated dye, or dye conjugated to a molecule of similar structure to BFA do not exhibit the same pattern of localization. The selective partitioning of conjugated BFA into intracellular membranes is probably due to its interaction with lipids as it is abolished by detergent extraction of lipids. These conjugates are the first dyes that bind the ER and Golgi complex without binding other prominent membrane bound compartments, and should prove useful as probes for the these organelles in living cells. The interaction of BFA with the ER and Golgi complex membranes may be essential to its effects on vesicular trafficking.